The synthesis of reactive conjugate clusters has been reported in numerous publications (see for example Maier et al., “Synthesis of Antisense Oligonucleotides Conjugated to a Multivalent Carbohydrate Cluster for Cellular Targeting,” Bioconjugate Chemistry, 2003, (14): 18-29; Rensen et al., “Design and Synthesis of Novel N-Acetylgalactosamine-Terminated Glycolipids for Targeting of Lipoproteins to the Hepatic Asiaglycoprotein Receptor,” J. Med. Chem. 2004, (47): 5798-5808; and U.S. Pat. No. 8,507,661).